While the method of the present invention is not intended to be so limited, for purposes of an exemplary showing it will be described in its application to conventional eyeglasses. As is recognized by persons who wear eyeglasses and by opticians, optometrists and ophthmologists who prescribe and fit eyeglasses, it is difficult during everyday use to keep eyeglasses in the proper position with respect to the pupils of the eye and on the bridge of the nose of the wearer. The maintaining of the proper position of eyewear on the nose is not only a matter of comfort, but is also necessary to obtain proper vision when the eyewear serves a corrective function. The problem is particularly acute for those who must wear bifocal, trifocal, or other multifocus types of eyeglasses that require percision alignment of the lenses with respect to the pupils of the eyes. This problem is accentuated during warm weather or when engaged in strenuous activities because perspiration has a tendency to lubricate the skin-ophthalmic support interfaces, causing the eyeglasses frequently to slip out of proper position.
Prior art workers have long recognized this problem and have pursued numerous approaches toward its solution. One approach is to provide an elastic O-ring or a metal or rubber spring at the points where the ear or temple pieces are hinged to the lens support frame. These devices cause the temple pieces to press against the head of the wearer yielding additional support to the eyewear. While helpful, this expedient is unsatisfactory for many due to the discomfort caused to the wearer by the pressure applied to the sides of the head by the temple pieces.
According to another approach, there is provided elastic or plastic cushioned nose and temple pieces that are affixed to or slipped on over the nose and temple pieces of the eyeglasses. Such devices have also not been completely satisfactory because they are unsightly and have a tendency to become slippery from contact with skin oils, perspiration, or water under conditions of high humidity, thereby losing much of their support capability. U.S. Pat. Nos. 538,151; 619,163; 2,561,402 and 3,582,193 teach exemplary forms of such devices.
Still another approach has been to attach thick, formed plastic, cushioned support pads to the nose pieces of the eyeglasses with pressure-sensitive adhesives or the like. The adhesives usually employing aromatic hydrocarbon solvents are applied to only one side of the pads and and are not intended for direct contact with the skin since such adhesives have a toxic effect on the sensitive skin of the nose and head. Additionally, such pads are unsightly and are subject to being lubricated by skin oils and/or perspiration.
An interesting approach is taught in U.S. Pat. No. 3,758,202. This reference describes additional support members attached to the lens frame portion of the glasses. The additional supports are provided with double-sided tape by which they may be secured directly to the face of the wearer. The support members are intended to take the place of the conventional temple pieces and even the nose bridge of the glasses may be eliminated. Such an approach to eyewear support is of course unsightly and difficult to use.
The present invention is based upon the discovery that the conventional ophthalmic support or frame of a pair of glasses may have some or all of its skin-contacting surfaces readily coated with a non-toxic, pressure-sensitive adhesive and that an unseen bond can be formed directly between these coated skin-contacting surfaces and the skin they contact. The adhesives contemplated by the present invention are not rapidly affected by natural skin oils, perspiration, water or the like under normal use conditions. The adhesives are non-toxic to the skin. The phrase "non-toxic" as used herein and in the claims is intended to refer to the fact that the adhesive, when in contact with the skin, will not have a harmful or adverse affect thereon.
The method of the present invention does not require the use of mechanical devices such as springs, O-rings, or the like. Nor does the method of the present invention rely on unsightly, preformed, manufactured pieces in the form of pads, shoes or the like which are slipped onto or affixed to the nose and/or temple pieces of the eyewear. Unlike the prior art, the method of the present invention does not rely upon an increased pressure on the skin or head of the wearer. The pressure-sensitive adhesives taught herein are resistant to natural skin oils, perspiration or water such as encountered under normal wear circumstances. The method of the present invention is particularly advantageous in the fitting and wearing of bifocal, trifocal and multifocal types of eyewear because it uses a thin adhesive layer which does not compress and which is not sufficiently thick to raise the eyewear above its normal fitted position on the nose or in a manner that would affect the focus of the eyewear.
Finally, the method of the present invention is comfortable for the wearer and the adhesives used are transparent or semi-transparent and are therefor virtually undetectable. In addition, the aesthetic or cosmetic appeal of the method of the present invention can be enhanced by the addition to the adhesive of an odorant, an anti-perspirant, or combinations thereof.